Skip to main content

Full text of "PHYSICS"

See other formats


Early Journal Content on JSTOR, Free to Anyone in the World 

This article is one of nearly 500,000 scholarly works digitized and made freely available to everyone in 
the world byJSTOR. 

Known as the Early Journal Content, this set of works include research articles, news, letters, and other 
writings published in more than 200 of the oldest leading academic journals. The works date from the 
mid-seventeenth to the early twentieth centuries. 

We encourage people to read and share the Early Journal Content openly and to tell others that this 
resource exists. People may post this content online or redistribute in any way for non-commercial 

Read more about Early Journal Content at 
journal-content . 

JSTOR is a digital library of academic journals, books, and primary source objects. JSTOR helps people 
discover, use, and build upon a wide range of content through a powerful research and teaching 
platform, and preserves this content for future generations. JSTOR is part of ITHAKA, a not-for-profit 
organization that also includes Ithaka S+R and Portico. For more information about JSTOR, please 


The course in physics is given in the eleventh grade, and con- 
tinues throughout the year, with a time allotment of six periods a 
week, two of which are consecutive for laboratory work. The class of 
twenty-four is divided into two sections for the laboratory work, and 
also for one of the other single periods, so that it may be utilized for 
either experiment or recitation. Prom the standpoint of subject mat- 
ter, the major topics covered by the recitations and experimental work 
do not greatly differ from the standard high-school course; nor, in- 
deed, can it be otherwise, since the course must meet the requirements 
of colleges to which our graduates are certified, and also be an ade- 
quate preparation for pupils going up for College Board examinations. 

There is no need, therefore, in presenting in this article the sub- 
ject matter of the course by listing the topics studied ; but rather it 
will be the purpose to show wherein methods of presentation have been 
developed which are in harmony with the fundamental principles 
which have been accepted as controlling all science work throughout 
the school, to indicate to what extent we have been successful in finding 
projects and problems in physics which the pupils have made their 
own and which they have pursued with that eagerness and zest which 
is the hall-mark of every project. Much has been written in favor of 
the project method of teaching science, and especially as a method for 
better physics teaching; but lists of projects, problems, questions, ex- 
periments, etc. which really work in the classroom and laboratory are 
difficult to find in print, and still more difficult to discover for oneself. 
Such lists will never be adequate for the needs of physics teachers until 
some plan is devised, whereby there may be a pooling of information 
and the results obtained by individual teachers may be made 
available to all. As a contribution in this direction, and not as a fin- 
ished piece of work, this article is written. It is the result of several 
years' effort to break away from the time-honored method of teaching 
physics by the assignment of lessons from textbook and laboratory 
manual, and to discover projects by which the interest of the pupil may 
be aroused and all his powers focused for educative effort. The trans- 
formation is not one which can be effected all at once. It is only by 
making a beginning here and there and gradually extending the num- 
ber and scope of projects that in time the whole of physics teaching 
may be successfully .remodeled. 


148 Francis W. Parker School 

The adoption of the project method for physics teaching at once 
makes impossible the usual method of assigning lessons, and neces- 
sitates the use of textbooks for reference purposes, and the use of a 
variety of the latter as a source of information on many topics. A well- 
chosen set of reference books will not only contain the necessary in- 
formation, but contain it in a way which is attractive and interesting 
to boys and girls of adolescent age. It is extremely important that 
assignments should be clear and definite. Nothing is more discourag- 
ing to the pupil, or destructive of his interest, than to be given hazy 
assignments, to come to feel that neither he nor the teacher knows 
exactly what is expected. It is of vital importance that the teacher 
should have gone over the ground carefully, and that assignments to 
reference books should be as definite and clear to the pupil as possible. 

This year pupils were asked to buy a standard textbook, in order 
that they might be sure of having a reference book, one which they 
might use most frequently. At the end of the article is appended a list 
of books which have been found useful and which are kept upon a 
special shelf in the grade room, where they are readily available for 
reference and use in study periods. Each book is provided with a long 
narrow strip of cardboard, bearing the title and library number of the 
book. A pupil taking out the book over night, or out of the room for 
study, signs his name on the slip and places it upon a spindle near the 
reference shelf. On returning the book he crosses off his name on the 
slip, replaces it in the book and returns the book to the shelf. This 
simple system prevents the abuse of reference books, renders checking 
them up easy, and at the same time keeps them readily available. 

The following is a list of topics, with correlated projects, prob- 
lems, questions, excursions, and experiments, which have been used in 
daily assignments. A number of these are given in full, with the ref- 
erences, to illustrate the method, while others are only listed. Many 
questions of this sort may be found at the ends of chapters in the more 
common textbooks, where they are placed for purposes of review. It is 
the raising of these questions in the mind of the pupil prior to the 
assignment which makes them worth while and significant. To the 
degree that the student makes them his own problems and seeks the 
answers by reason of his own desire to know, to that extent they become 
projects and the pupil's efforts educative. This is the vital distinction 
between the old and new methods. The information is sought as a re- 
sult of a question which the pupil desires to answer, and the question 
is not given as a test of the thoroughness with which facts and prin- 

Ybab Book 149 

ciples have been learned through the reading of a textbook. To this 
extent, the project method is the reverse of the plan usually followed. 

Measurement. — How do people measure things? 
How does the grocer measure vegetables ? onions or potatoes ? vinegar ? 
How does the druggist measure out powdered medicines? liquids? 
What kind of weights does the jeweler use in determining the value of 

diamonds and other precious stones ? 
Visit a grocery, a drug-store, and a jewelry shop, and get all needed 

What other units of measurement are used at home ? 
Make a list of all units found, and show how they are related. 

Reference. — Measurements for the Household (Circular, Bureau of 
Standards, No. 55). 

How is the public protected from false measurements and uniformity 
in weights and measures secured ? 

What are some common ways by which dishonest merchants and deal- 
ers cheat in weighing and measuring commodities ? 

How does the city government protect us against these practices ? 

What precautions should we adopt to further protect ourselves ? 

Excursion to City Sealer's office to hear of the work of this depart- 
ment of the city government, and to see exhibits of confiscated 
scales, weights, and measures. 
Reference. — Measurements for the Household (Circular, Bureau of 

Standards, No. 55), pp. 1-36, 136-143. 

Why is the metric system used for all science work the world over and 

constantly coming into more general use ? 
How many centimeters tall are you ? How many meters ? 
How many kilograms do you weigh? How many grams? 
What does milk cost per liter? 

How many miles is it to Evanston ? How many kilometers ? 
What is the meaning of the prefixes milli-, centi-, dekor-, hecto-, kilo-, 

as used in the metric system? 
Problems 1, 3, 4, and 5, p. 7, MilKkan and Gale. 

References. — MilKkan and Gale, pp. 1-7; Black and Davis, pp. 1-8. 

Pressure in Liquids. — What kind of pressure does a submarine with- 
stand ? Is there any limit to the depth to which a submarine may 
descend ? 

How does the submarine dive and emerge at will ? 

150 Fkancis W. Parker School 

What is the record in deep-sea diving ? What diflBculties does the diver 
experience in his work ? Would a diver experience any more diffi- 
culty in working in Salt Lake than in Lake Michigan? What has 
the density to do with it ? 
Laboratory experiments to answer above questions. Determination of 
change in water pressure per vertical foot, by using a pressure 
gage and noting readings at taps on the various floors in the 
school building. Experiment with balancing columns performed 
by a part of the class. 
Problems 2, 3, 6, and 8 ; pp. 14 and 15, Millikan and Gale. 

References. — Millikan and Gale, Chap. II; Black and Daws, Chap. Ill; 
Mann and Twiss, Chap. IV ; How it Works, Chap. XVIII ; Twenty Thousand 
Leagues Under the Sea; magazine articles and newspaper clippings on sub- 
marine construction, operation, and dangers. 

What maintains the pressure in the city mains? Why is a constant 

pressure necessary? 
How does the hydraulic elevator work ? 
How does the hydraulic press operate ?* 
Excursion to visit a pumping-station in a down-town office building 

to see pumps and elevators in operation. 

Buoyancy or Principle of Archimedes. — When you float or swim in 

water, what becomes of your lost weight? 
Why does a heavy stone seem so much lighter when lifted under water ? 
What is your density if you can just float in water? What is your 

volume in cubic feet? 
Why does iron float on mercury ? (Demonstration experiment to show 

it.) Are there any .metals which would sink in mercury ? 
Laboratory experiments to find density of quartz, aluminum, pine, 

gasoline, milk, and cream. 
Problems 1, 2, 6, 9, 10, 11, 12, 13 ; p. 25, Millikan and Gale. 

The Atmosphere.-^-Hovf much pressure does the air exert? 

Demonstration experiments. — ^A square can is crushed by boiling in 
it a small amount of water, fitting with a tight stopper, and sub- 
sequent cooling. A pupil is lifted from his feet by the use of 
Magdeburg spheres, and other more familiar experiments. 

Why does the barometer change from day to day ? 

•In the class discussion of the hydraulic press, an interesting description of an oil 

£ress for removing car wheels from axles was given by a member of the class, who 
ad seen it in operation at the West Side Car Shops. 

Ykab Book 151 

What relation is there between the readings of the barometer and the 

weather ? What may be expected if the barometer falls rapidly ? 

Eises rapidly ? 
What causes a cold wave ? A hot wave ? 
Observe the recording barometer (barograph) and the changes from 

day today. 
Compare your observations with the weather forecast and the weather 

maps posted in the hall. 

References. — MUlikan and Gale, pp. 86-34; Black and Davis, pp. 75-93; 
Our Ovm Weather; About the Weather; Book of Wonders, pp. 38, 40, 213, 
843, 398, 400; Careers of Danger and Daring; Chap, on The Baloonist; Story 
of Great Inventions, parts of Chaps. IV and VI ; set of weather maps showing 
course of the record blizzard and cold wave of January, 1918. 
Project. — Construction of a water barometer in main stairway of the 

Moisture in the Atmosphere. — What is the cause of the discomfort one 

feels on a muggy summer day? 
How do people in warm countries cool their drinking water without 

Explain the "sweating" of the ice-water pitcher. Why is it not seen 

in winter? 
In very cold weather, any unfrozen body of water appears to be steam- 
ing hot. Explain this phenomenon. 
What becomes of the white cloud from the exhaust-pipe of a steam 

engine? Is it steam? 
What are the atmospheric conditions which produce rain, fog, dew, 

frost, snow, and hail? 

References. — Millikan and Gale, parts of Chap. IV; Black and Davis, 
pp. 810-217; Mann and Twiss, pp. 125-131; About the Weather, Chaps. XII 
and XXI ; Our Own Weather, Chap. XIII ; Circular, Bureau of Standards, 
No. 55, Chap. VIII. 

Why is it desirable to have the relative humidity in school and living 
rooms between 40 and 60% ? 

Why is it more difficult to maintain a proper humidity in severe win- 
ter weather ? 

What means can be used to increase the moisture content of the air 
we breathe? 

Experiments on cooling by evaporation, determining the dew point, 
and testing the relative humidity in various rooms of the school, 
using sling-psychrometer.* 

•For a fuller account of the study of relative humidity, see article in Year Book IV, 
School Hiating and VentUatian, — A Study in Applied Physics, p. 126. 

152 Francis W. Parker School 

Applications of Atmospheric Pressure. — Why not fill automobile tires 
with water ? How does a gas differ from a liquid ? 

Why does a balloon go up ? What determines its lifting power ? 

An observation balloon is constructed to lift a total weight of 350 lbs. 
How many cubic feet of hydrogen must it contain ? 

Study the working of lift- and force-pumps, the air-brake, and the 

Demonstration experiments and models used in explaining these ap- 

Laboratory experiment to find out the effect of pressure on a gas 
(Boyle's Law). 

Force. — ^What kinds of force are there ? Are any of them visible ? 
Gravitation is said to be the "universal" force. Explain. 
What keeps an aeroplane from falling ? 
Why is it dangerous to stand upright in a canoe ? 
What is meant by "center of gravity?" Where is this center in a 
meter stick, a gate, a hoop, any body of regular shape ? 

Accelerated Motion. — ^What is meant by the term "pick up" as applied 

to an automobile? 
If an automobile accelerates at the rate of 4 ft. per sec, in how many 

seconds will it acquire a speed of 60 miles per hour? How far 

will it travel in gaining this speed? 
A street-car has a negative acceleration of 4 ft. per sec. in stopping. 

How far from the corner must the motorman apply the brakes in 

order to make the stop properly, if his car is traveling at the rate 

of 30 miles an hour? 
Experimental derivation of the laws of falling bodies with Hawkes- 

Atwood machine. 
Problems 1 to 12, pp. 99-100, Millikan and Gale. 

Molecular Forces. — Why does oil ascend in a wick and ink in a blotter ? 

Why should gardens be frequently cultivated in dry weather? 

Why is charcoal used in filtering water and as a lining in the walls of 
refrigerators ? 

Why does falling water separate into small drops? Explain the ap- 
pearance of a drop of water on a dusty surface. 

Temperature Effects. — What kind of thermometers are there? What 
kind would you take on a polar expedition ? 

Is there any advantage in using a Fahrenheit or a Centigrade ther^ 
mometer ? 

Yeae Book 153 

How are low temperatures obtained in the laboratory? 

Demonstration experiments on artificial cooling. 

Laboratory experiment on finding the corrections for the laboratory 
thermometers at the freezing- and boiling-points. 

Why do not lakes and rivers, freeze from the bottom up ? 

How are fine watches made independent of temperature changes ? 

Why does the school clock tend to gain time during the winter months, 
and especially over the week-ends? How may this be corrected? 

Why is a silver knife placed in a glass jar when fruit is being canned ? 

Formerly the wires which carry the electric current into an incan- 
descent bulb were of platinum. Why? An alloy is now used in- 
stead of the platinum. What must be true of the way this alloy 
expands and contracts? 

Mechanics. — Is there any such thing as perpetual motion? Is a per- 
petual-motion machine a possibility? 
What is meant by "work" as this term is used in physics ? 
What simple machines are used in moving heavy weights? 
All complex machines are built out of simpler parts — levers, wheels, 

axles, cranks, worm-gears, pulleys, etc. What ones are found in 

the bicycle ? The sewing machine ? 
Examine the mechanism of your victrola. What simple machines can 

you recognize? How is the speed kept constant? 
What is meant by the term "mechanical advantage?" What is the 

"mechanical advantage" of the simple machines mentioned above ? 
Laboratory experiments on the principle of moments, levers, pulleys, 

and inclined plane. 
Excursion to the West Side repair-shops to see machines of many 


What is meant by "white coal ?" How is it utilized ? 

What kinds qf water wheels are there? Under what conditions does 

each kind operate to best advantage ? 
"All energy comes from the sun." Check up on this statement for all 

examples that you can think of. 
How is power measured ? 

References. — Millikan and Gale, pp. 147-152, 156-159 ; Black and Davis, pp. 
71-72, 37-39; About Engineering, Chaps. Ill, IV, and XII; Mann and Twiss, 
Chap. V. 

Heat. — What is heat? How is it measured? What relation has heat 
to friction ? 

154 Francis W. Parker School 

What metal would you use to make a hot-water bottle? 

Why is ice a better refrigerating agent than cold water? 

Why does not all the snow melt when the temperature gets above 0° C. ? 

What relation has Lake Michigan to the Chicago climate ? 

Why does live steam produce more severe bums than boiling water? 

Laboratory experiments on heat of fusion of ice and vaporization of 
steam ; half of class doing one and half the other. 

How is ice made ? Excursion to ice plant of Consumers' Company to 
answer this question. 

Investigate your home heating-plant and find out how it works. Get 
full information and make a diagram, with explanation, for your 

What is good ventilation ? How is it secured in the school ? What are 
the difficulties in our system? 

Excursion through the school plant to see boilers, intakes, humidify- 
ing and ventilation devices. 

Tests made on school ventilation system to determine its efficiency.* 

Utilization of Heat for Power. — How is heat converted into mechan- 
ical power ? Why are great losses inevitable ? 

How does the steam-engine work? Why does the expansion of the 
steam cool it? 

What is meant by a double or triple expansion steam-engine ? A single- 
acting or double-acting steam-engine? 

How is a steam-turbine constructed and how does it work? 

What happens in the piston-chamber of a gasoline engine? What is 
the difference between a 4-cycle and a 2-cycle gas-engine? Of 
which sort is an automobile engine ? 

In what order are the cylinders of a 4-cylinder automobile engine 
fired? 6-cylinder? 8-cylinder? 13-cylinder? 

Why is a cooling system needed on a gas-engine ? What advantage has 
an air-cooled motor over a water-cooled one ? Which kind is used 
for aeroplanes ? 

References. — Millikan and Gale, pp. 185-195 ; Slack and Davis. Chap. XII ; 
Hall, Chap. XIX; The Story of Great Inventions, first part of Chap. Ill, 
pp. 150-172; All About Engineering, Chap. V; Book of Wonders, pp. 181-190; 
How It Works, Chaps. I-IV, inclusive; catalogs and circulars from auto- 
mobile companies, and from companies supplying automobile accessories. 

*See article in Year Book, Vol. IV, "School Heating and Ventilation — A Study in 
Applied Physics." 

Year Book 155 

Magnetism. — ^Why is iron sometimes magnetic and sometimes not? 

How are magnets made ? 
Why does a compass point north ? Can the compass always be trusted ? 
What uses do we make of magnets? 
Laboratory experiments on magnetism and magnetic fields. 

Electricity. — What is electricity? How is lightning produced? 

Why do thunder storms occur chiefly in summer? 

Does a lightning-rod protect from lightning ? How does it work ? Why 
are lightning-rods not used in the city? 

Study the action of the condenser and the electrophorus. 

How is a battery made, and how does it produce an electric current? 

What diflSculties have to be overcome to make a good battery ? 

What are some common commercial types ? 

What are the merits of each type ? 

Laboratory experiments on the Voltaic cell, and methods of overcom- 
ing polarization arid local action. 

What makes the current flow in any electrical circuit? 

How could you find out the direction in which the current flows in 
the trolley-wire on North Clark street? 

How is electricity measured? Define the units. 

What factors determine electrical resistance ? 

Laboratory experiment to determine these factors and effect of each. 

How would you determine the resistance of an electric lamp ? A coil 
of wire? A battery? The answers to this question are worked 
out by means of demonstration experiments. 

What is a shunt? How does the current divide in a shunted circuit? 

How does the electric current decompose water ? 

How would you silver-plate any metallic articles ? 

Demonstration experiments to show electrolysis in silver-plating. 

How is an electrotype made ? 

How may a plate of pure copper be made from an impure one ? 

If two wires were connected to a source of electrical current, could you 

tell which one was positive and which negative ? How would you 

find out? 
How does the storage-battery work? What happens on charge? On 

discharge ? 
Laboratory experiment on the storage battery. 

References.— MUlikan and Gale, pp. 267-373 ; Black and Davis, pp. 348-355 ; 

156 Francis W. Parker School 

Electricity and Magnetism, pp. 522-528; Mann and Twiss, pp. 201-2; Elec- 
tricity, WoodhuU, Chap. V. 

What makes an electric bell ring? How is the door of an apartment 
opened by electricity from each apartment in the building ? 

How is the strength of an electro-magnet measured? 

Make a wiring plan to ring a bell by either of two push-buttons, one 
located at the front and one at the back door. Make a similar 
plan by which one button would ring two bells, one up stairs and 
the other down stairs. 

How does the telegraph line work ? Be able to make a diagram to show 
the connections in the path of the current. 

A telegraph line is set up in the laboratory and used for some days by 
groups of pupils. 

References. — Millikan and Gale, pp. 872-278 ; Black and Davis, pp. 271-279 ; 
Mann and Twiss, pp. 166-169 ; Electricity and Magnetism, Chap. XII ; How it 
Works, Chap. VI; Electricity, Chaps. VI and XVIII. 

How does an arc-light differ fi-om an incandescent lamp? 

Why are lamps in a house always connected in parallel ? 

What kind of electric lights are most efficient? 

On what basis do you pay for electric light? Secure an old electric 

light bill, and find out what the terms on it mean. 
How much does it cost to operate your vacuum cleaner ? Your electric 

flat-iron ? 
Why is the consumption of electricity for heat the most expensive way 

to use it? 
Make a plan for wiring a four-room flat. 
Laboratory experiments on determining the efficiency of carbon and 

tungsten lamps, and the cost of operating them. 
How does the dynamo generate an electric current ? 
What is the difference between a D. C. dynamo and an A. C. generator ? 
Why is the A. C. type used in all large installations ? 
How is a motor different from a dynamo? 
Why does a motor require more current when starting than after it is 

running at a higher speed ? 
In the study of the dynamo, large diagrams are useful in tracing the 

currents and for the applying of the dynamo and motor rules. 
How does the induction-coil produce a current of high electromotive 

force? For what purposes are such coils used? Why does the 

spark occur at the "break" instead of the "make?" 

Yeae Book 157 

How is a transformer different from an induction-coil ? 

What is self-induction ? Why is it an important factor in all A, C. 

circuits ? 
Why is power transmitted long distances only at very high voltage, 

and why is it always A. C. rather than D. C. current? 
Laboratory experiments on induced currents, motor, induction-coil, 

and transformer. 
What is the meaning of the terms single phase or three phase as ap- 
plied to A. C. Currents ? 
How can storage batteries be charged, when the only source of supply 

is A. C. current? 
How is conversation transmitted by telephone? What are the steps, 

connections, and circuits involved in making a call through a 

central station ? 
How is it possible to ring the telephone bell at a subscriber's although 

the circuit is open? 

Sound. — How is sound produced and transmitted? Why does sound 
travel faster in water than in air? In hydrogen than in air? 

What is an echo ? Why are echoes noticeable only in large halls or out 
of doors? How may echoes be prevented in halls and audito- 

Sound-proof rooms are needed in the battle-ships of the navy. How 
would you construct such a room? 

Why are sounding-boards used in connection with all stringed instru- 
ments? What causes sounds to differ in pitch? How may the 
pitch of a violin string be changed? 

How does a bell, at a crossing, change in pitch as you pass it on a 
rapidly moving train? 

What is resonance? Under what conditions is it produced? 

Why does a large sea shell always seem to be giving off sounds of its 

What is the difference between noise and music ? 

Why is the same note different when sounded on a flixte, piano, or 
violin ? 

How does a bugler vary the pitch of the notes he produces? 

How is a phonograph record made, and how is it reproduced? 

Laboratory experiments on finding the velocity of sound, the pitch of 
a tuning-fork, resonance. 

158 Francis W. Parker School 

Light. — What produces an eclipse of the moon? Of the sun? "Why is 
a total eclipse of the sun very rare? A partial eclipse of the sun 
occurred June 8. Why was it partial here, but total at Denver, 
Colorado ? 

What is the cause of twilight ? Why is twilight short at the equator, 
getting longer as you go either north or south? 

How do astronomers measure the distance between the stars? 

What properties would a perfect mirror possess? How is an ordinary 
mirror made? 

When you walk towards the mirror, how rapidly do you appear to 
approach your image? Explain. 

Why does an oar reaching into the water appear bent at the water line ? 

How is light-giving power measured? How is the intensity of illumi- 
nation measured ? How much illumination is needed for reading ? 
Sewing ? 

How does a photometer work ? 

Laboratory experiments, on finding the velocity of light in water and 
in glass, and the laws of reflection. 

Why do curved mirrors produce such distorted images ? 

Why is a lens necessary in a camera ? 

Hov? is a microscope constructed and how does it work? Telescope? 
Opera-glass? Projection lantern ? 

What is meant by magnifying power "^ How is it found for the above 
inetniments ? 

Why do you need two eyes for seeing ? 

What sort of lenses do near-sighted people wear ? Par-sighted ? 

Laboratory experiments on convex lenses, concave mirrors, the micro- 
scope and telescope. 

What is the cause of color? Why does a prism break up light into 
several distinct colors? 

What makes the rainbow ? Why is not the rainbow seen in the morning 
or at noon? 

What does it mean to be color-blind ? 

How is colored printing done ? How is a colored photograph produced ? 

What is the spectrum ? What kinds of spectra are there ? 

How does the spectroscope work ? How does it tell us about the com- 
position of stars and the rate of motion of the heavenly bodies ? 

Laboratory experiments on the spectroscope, dispersion and color. 

What is the relation between light, electric waves, and X-rays ? 

How are X-rays produced ? Are they dangerous ? 

Year Book 159 

What relation is there between radium and X-rays ? 

What indications does radio-activity give us concerning the nature of 

matter ? 


Story of Great Inventions E. E. Burns (Harper) 

All about Engineering.. G. D. Knox (Cassell) 

Careers of Danger and Daring .C. Moffett (Century) 

How it Works A. Williams (Nelson) 

With Men Who Do Things A. R. Bond (Munn) 

Mechanics, Indoors and Out F. D. Hodson (Doubleday) 

Boys' Book of Model Aeroplanes Collins (Century) 

Boys' Second Book of Model Aeroplanes Collins (Century) 

Panama and the Canal A. B. Hall (Newson) 

About the Weather M. W. Harrington (Appleton) 

Our Own Weather E. C. Maitin (Harper) 

Electricity and Its Everyday Uses J. F. WoodhuU (Doubleday) 

The A B C of Electricity Meadowcraft (Excelsior Pub. Co.) 

Wonderbook of Light E. J. Houston (Stokes) 

The Book of Wonders 

Conversations on Electricity J. G. Branch (Rand-McNally) 

Elementary Lessons on Electricity and Magnetism. .Thompson (Macmillan) 

Several copies of each of the standard text books. 

Copies of circular of Bureau of Standards, No. 55, Measurements for the 

Copies of monographs of Joint Committee Series, N. E. A. 
Current copies of Everyday Engineering, Scientific American, and Popular 

A large number of selected articles from these magazines have been bound 

separately and are available for particular assignments.